Abstract
Purpose: :
To assess the intermediate term effect, which has not been previously evaluated, on retinal capillary blood flow in patients who have received multiple intraocular anti-VEGF injections. We previously showed that a statistically significant acute decrease in total retinal capillary blood was seen in all the patients immediately after the IVT injection that was related to the transient injection related IOP spike (Haji and Frenkel 2010 AGS poster).
Methods: :
Retinal capillary blood flow was measured on 8 patients before and right after ranibizumab IVT injection with scanning laser Doppler flowmetry. Of the eight patients four had glaucoma. The retinal capillary blood flow was measured at superotemporal retina (STR) and inferotemporal retina (ITR) adjacent to the optic nerve. Combined STR and ITR were also analyzed. Two years later blood flow measurements were repeated in the same manner in all the eight patients just before IVT injection.
Results: :
In the 2 year interim the patients had an average of 17 injections. Initial mean flow and flow after a 2 year interval for STR was 295 +/-85 and 244 +/-72; for ITR was 249 +/-59 and 235 +/- 60; for combined was 544+/-133 and 479 +/-118. P =0.2, 0.65, and 0.35 respectively. The differences were 9%, 6% and 12% reductions. In the group of glaucoma patients the initial mean flow and flow after a 2 year interval for STR was 294+/-88 and 188 +/- 44, for ITR was 249+/-62 and 207+/- 34, the combined mean blood flow was 543+/-141 and 395 +/-41. P=0.08, 0.46 and 0.17 respectively. The differences were 36% 15% and 27% reductions. The STR and the combined retinal capillary blood flow in the glaucoma group showed reduction however, it was statically insignificant.
Conclusions: :
The initial acute IOP spike related decrease in retinal capillary blood flow is not significantly sustained in patients who have had multiple intraocular Anti-VEGF injections over a two year time span. However, in glaucoma patients a trend towards a long term reduction in retinal capillary blood flow was seen (though statistically not significant). Further study with larger patient population is warranted.
Keywords: vascular endothelial growth factor • age-related macular degeneration • intraocular pressure